In motors of this type, the electronic control unit supplies power to the motor output stages, which ordinarily include semiconductor switches and windings. The control unit is usually designed for bidirectional operating conditions. If the motor drives a fan, for example, the current rises in proportion to the squared motor speed, while the motor speed rises in linear proportion to the supply voltage. If fans of this type are used in a motor vehicle and fed from the vehicle battery, the motors are designed for a nominal voltage of 13 V, for example, but must operate dependably at a voltage of up to 16V, for example. The fan must provide the necessary air capacity at the nominal voltage. The higher air capacity available at higher battery voltages is therefore superfluous. However, these stipulations mean that the motor and the electronic components must be designed for higher performance ratings around 16V.